This invention is an improved automobile passive safety device of the type having a shoulder safety belt extending diagonally across the upper body of a passenger.
Various safety belt devices are known which are referred to as passive safety devices. In such devices the passenger need not put on or take off the restraining device since this occurs automatically on closing and opening, respectively, of the vehicle door. Passive safety devices have come into increasing use of late due to the fact that many vehicle occupants, for reasons of convenience or otherwise, do not use the safety belts provided for their own protection.
Several forms for these devices are known. In German OS 22 47 595, a passive device is shown in which a safety belt is fixed on the vehicle door at shoulder level of the vehicle occupant. The belt is displaced from a removed position wherein the belt is lifted away from the automobile passenger to a restraining position wherein the belt extends across the upper body of the passenger automatically upon opening and closing of the vehicle door, respectively. In German OS 22 54 103 and German OS 25 22 415, the door-side end of a diagonally-extending shoulder safety belt is fastened on a slide supported in a guide in the side region on the vehicle body. The slide is displaceable by means of a driving device, for example, a vacuum-actuated piston-cylinder unit or an electric motor, from the removed position to the restraining position. Even though it is a passive restraining device not normally intended to be attached and unhooked by the passenger, the door-side end of the belt may be attached to the slide by an emergency opening lock which will normally be engaged (see for example German OS 22 47 595 and German OS 25 05 971). This will facilitate the removal of the safety belt in an emergency situation, for example, after a vehicle accident, should the restraining device become permanently locked in place either at the door-side or at the other end of the belt, where there is generally a belt take up and winding mechanism.
In passive safety devices of this type, it is also common to use an electric switch arranged in the belt lock which, when the belt is not connected, either prevents the starting of the motor (an interlock system), or which sets off a signal to the driver indicating that the safety belt or belts have not been attached. See for example, U.S. Pat. No. 3,133,277; U.S. Pat. No. 3,147,819; U.S. Pat. No. 3,570,621; or German OS 20 06 029.
An interlock system or a warning system which operates with such an electric switch can be difficult to incorporate into a passive safety device in which one end of the safety belt is fastened to a belt lock in a displaceable slide. If the switch is built into the belt lock, not only the switch but also the electric wires leading to the switch must be moved back and forth when the slide moves. Also, the other end of the safety belt is generally contained in a winding mechanism arranged between the vehicle seats, and the electric lead-ins and lead-outs can be run to the belt lock only with considerable difficulty.